Mayor Bill de Blasio postponed his trip to Italy Friday in the wake of the news that a Staten Island man died of a heart attack after being handcuffed Thursday afternoon, police said.

The mayor's office said in a statement that de Blasio delayed his trip until Saturday to "attend to city business."

Eric Garner, 43, was arrested for allegedly selling untaxed cigarettes, police said. While he was being handcuffed, he went into cardiac arrest, police said. He was taken to Richmond University Medical Center, where he was pronounced dead.

A video obtained by the Daily News showed that Garner was put in a chokehold while under arrest, and shouted "I can't breathe, I can't breathe!"

Chokeholds are prohibited by the NYPD, according to police commissioner Bill Bratton.

In the video, Garner insists he was just "minding my own business." According to the Staten Island Advance, Garner had three pending criminal cases against him, all involving untaxed cigarettes.

In a press conference Friday afternoon, de Blasio said he was "troubled" by the video, but he said he couldn't pass judgment on "a video alone" until a "full and thorough investigation."

Bratton said the two officers involved in the incident had been reassigned to desk duty since the incident.

One police source told the Advance that Garner "absolutely resisted arrest. He took a fighting stance."

However, another eyewitness told the Daily News that Garner was "breaking up a fight" nearby when he was approached by police.

According to multiple reports, Garner weighed at least 350 pounds and the Daily News reported he had asthma.

Staten Island District Attorney Daniel Donovan told the Advance that his office is "working with the NYPD to do a complete and thorough investigation surrounding Mr. Garner's death."